The present invention relates to a method of and apparatus for heat-treating or performing steam-setting operation on the bobbins of yarn produced by a spinning machine as the bobbins are transferred from the spinning machine to a winding machine.
In the spinning process, sliver of raw cotton, wool and synthetic fiber is spun into yarn which is wound on bobbins. The finished yarn on the bobbins is then wound by the winding machine into a so-called corn cheese or parallel cheese. When a new bobbin is supplied to the winding machine, the ends of yarn should be joined.
If, however, the spun yarn is not heat-treated or steam-set, the twisting torque of the yarn that was applied during the spinning process interferes with the yarn end jointing process. That is, in the automatic yarn jointing device, the yarn end does not become aligned in the direction of the carrier air flow due to the twisting torque, resulting in a failure of the yarn end jointing.
For this reason, the bobbin of finished yarn is steam-set before being fed to the winding machine to remove the twisting torque.
Conventionally, the bobbins are randomly thrown into a bobbin case and several tens of these bobbin cases are loaded into an oven where they are subjected to a heat treatment or steam-setting operation.
The steam-setting procedure consists of collecting into the bobbin case a specified number of finished yarn bobbins produced by spinning machines, transporting the bobbins to the oven installed in a room separate from the spinning room, performing the steam-setting on the bobbins, removing the bobbins from the oven and then carrying the heat-treated bobbins to the winding machine where they are fitted on each of the spindles of the winding machine.
In the above procedure, the process of removing the bobbins from the spinning machine and that of fitting the bobbins on the winding machine are each automated. However, the steam-setting process which is between the above two automated processes is not automated an requires associated transporting work. That is, a batch of bobbins in a specified number is carried to the oven for steam-setting. After the steam-setting, the processed bobbins are transported to the winding machine.
In other words, the provision of the steam-setting process for heat-treating the bobbins at a location between the spinning machine and the winding machine requires a series of additional processes as follows.
(1) a process of winding the spun yarn on the bobbin as it is produced by the spinning machine; PA0 (2) a process of putting a specified number of bobbins in a case and transporting the case to the oven; PA0 (3) a process of transporting the bobbins contained in the case to the steam-setting equipment; PA0 (4) a process of removing steam-set bobbins from the steam-setting equipment; and PA0 (5) a process of fitting the steam-set bobbins on the winding machine.
The processes of removing the bobbins from the spinning machine and fitting them on the winding machine are automated relatively easily. The steam-setting process, however, is independent of other processes and this is a major obstacle to making these processes an automated continuous series of processings. The fact that the bobbins are not easy to handle and that the time required for the steam-setting is different from other processing times has also contributed to preventing this process from being a part of the automated series of processings.
In the heat treatment of the bobbins, the time and temperature required for the evacuation process vary depending on the kind of yarn wound on the bobbins, such as whether the yarn is made of wool, cotton or mixed stuff with synthetic fiber.
There is a trend in recent years that the number of bobbins produced per unit of time has been increasing as the spinning machine is being uprated for higher speed. However, with the above-mentioned batch processing method for steam-setting, the entire series of processings is made complicated and difficult to be fully automated.
Although some continuous heat treatment apparatus have been considered in the past, they are large in size, requiring a large installation space, and it has been difficult to install a heat treatment apparatus with a sufficient processing capacity between the spinning machine and the winding machine.